High speed duplicating and printing devices will typically deliver sheets of paper and other paper-like stock at some exit port on the device with a particular edge of each sheet serving as a leading edge, that is the edge first to leave the device. The range of known duplicating and printing devices, in addition to other paper transporting devices, are known to move and deliver a wide range of sizes and weight of paper stock with a number of different kinds of known inks, fusing oils and the like, in both simplex and duplex modes. Given this variety of paper stock which is delivered at the exit ports of the various devices, there is a corresponding great variation in the beam strength of the various paper stock and in the surface characteristics of the various paper stocks, including nature and quality of print ink, surface finish and texture.
In many paper handling systems it is necessary to transport the paper sheets between various paper handling devices. It often arises in such systems that the leading edge presented by the delivering device is not the optimal sheet edge for purposes of handling within the receiving device. Consequently the need arises for a method and apparatus for rotating each delivered sheet through an arc which is usually ninety degrees so that the leading edge of each sheet presented to the receiving device is not the leading edge which was delivered from the delivering device, but is rather one of the adjacent edges of the typically rectangular sheet. For instance, if sheets are delivered by a duplicating device with their long edges leading, but the receiving sorting device has been optimally set up to receive and sort sheets which are delivered with their short edge leading, each sheet must be rotated through an arc of 90 degrees between when it leaves the duplicating device and when it arrives at the sorting device.
A number of devices have been proposed in the art to the apparent purpose of meeting the above need. However it does not appear that any of the known devices have been functional at all without substantial complexity, resulting in expense of manufacturing and maintenance and unacceptably high breakdown, jamming, and other downtime failure modes. It also does not appear that any of the known devices are capable of receiving and rotating paper stock sheets at the rates at which state of the high speed duplicating and printing devices are capable of delivering them. This sheet delivery rate is frequently in excess of 170 sheets per minute, and advances in the rapidly changing sheet handling technology will likely soon result in even higher sheet delivery rates. Neither does it appear that any known devices are suitable for, or capable of, receiving, without adjustment, a series of sheets having differing lengths and widths and then rotating each of the sheets, regardless of differing lengths and widths, through a uniform arc smoothly and without damage to the sheets.
There is therefore a need for a method and an apparatus for receiving from one paper handling device, at a high rate of delivery, paper sheets of varying dimensions and stock weight with varying qualities of paper surface characteristics, and with printing on one or both sides of the sheet, and then rotating each of those sheets through the required arc so that they may thereafter be delivered at the same rate of speed from the apparatus to the next paper handling device with the appropriate edge for that device now leading that sheet.